TinO2n-1 Suboxide Phases in TiO2/C Nanocomposites Engineered by Non-hydrolytic Sol-Gel with Enhanced Electrocatalytic Properties.

Shuxian Zou,Romain Berthelot,Pierre Hubert Mutin,Bruno Boury,Nicolas Brun

doi:10.3390/nano10091789

Abstract

We report a non-hydrolytic sol-gel (NHSG) route to engineer original mesoporous TinO2n−1@TiO2/C nanocomposites. The synthetic approach is straightforward, solvent-free, additive-free, and meets the challenge of atom economy, as it merely involves TiCl4 and THF in stoichiometric amounts. We found that these nanocomposites present enhanced electrocatalytic properties towards the oxygen reduction reaction (ORR) in 0.1 M KOH. We believe that these preliminary results will open a window of opportunity for the design of metal suboxides/carbon nanocomposites through NHSG routes.

Highlights

Titanium suboxides have received considerable attention in the last decades due to their remarkable electronic and optical properties [1,2,3]
We reported on the synthesis of TiO2 nanocrystals and TiO2/C nanocomposites from TiCl4 and THF [42]
The non-hydrolytic sol-gel (NHSG) route allowed producing TinO2n−1@TiO2/C nanocomposites by a straightforward solvent-free, additive-free approach that meets the challenge of atom economy, as it merely involves TiCl4 and THF in stoichiometric amounts

Summary

Introduction

Titanium suboxides have received considerable attention in the last decades due to their remarkable electronic and optical properties [1,2,3]. In contrast to Magnéli phases, Ti3O5 structures [10] (TinO2n−1, where n = 3) have no CS planes. As they satisfy the TinO2n−1 formula, Ti3O5 polymorphs have often been considered as the first members of the Magnéli phases’ family. Titanium suboxides depict remarkable properties [3,11,12], amongst which are electrochemical stability, high electronic conductivity (c.a. 10.4 S cm−1 for Ti4O7 at room temperature [13]), high electron mobility (>0.5 cm V−1 s−1 for Ti4O7 at room temperature [1]), and low band-gap as compared with stoichiometric TiO2 (about 0.5 eV smaller than that of TiO2 anatase [14]). Titanium suboxides have been widely investigated in electrocatalysis [15,16,17,18,19], photocatalysis [20,21,22,23] and energy storage devices [24,25]

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Results

Conclusion